Automatic test equipment (ATE) refers to an automated, usually computer-driven, system for testing devices, such as semiconductors, electronic circuits, and printed circuit board assemblies. A device tested by ATE is referred to as a device under test (DUT).
ATE typically includes a computer system and a testing device or a single device having corresponding functionality. Pin electronics are typically part of the testing device. Pin electronics includes drivers, comparators and/or active load functionality for testing a DUT. The drivers provide test signals to pins on the testing device.
ATE is capable of providing different types of signals to a DUT. Among these signals are test signals, which are used to test the DUT, and programming signals, which are used, e.g., to program an EPROM (Electrically Programmable Read-Only Memory) on the DUT. The test signals and programming signals, in particular, require paths having different impedance. More specifically, the programming signals are typically required to have a relatively high voltage. As such, it is best to drive the programming signals over a relatively low impedance path. This is done in order to prevent significant voltage drops and to ensure a relatively constant voltage in response to changes in load current. Testing signals are driven over an impedance path that is configured to match the impedance of the DUT and thereby reduce signal reflections from the DUT. The impedance path over which the test signals are driven has relatively high impedance, typically.